This invention relates to a jig for producing rectangular electronic components with side electrodes as exemplified by laminated ceramic capacitors and network resistors. More particularly, the invention relates to a jig for assisting in the application of a conductive paint onto end faces of electronic components in a rectangular plate form, thereby forming side electrodes.
Certain types of electronic components such as laminated ceramic capacitors have side electrodes. To form such side electrodes, a jig generally indicated by 20 in FIGS. 13a, 13b, 14a and 14b is conventionally employed in a manner typically described in Japanese Patent Publication (kokoku) Nos. 11488/1987 and 20685/1987. As shown, jig 20 comprises a rectangular frame 21 defining its periphery, an elastic sheet 22 fitted in the frame 21, and a core sheet 23 that is embedded in the elastic sheet 22 and secured to the frame 21. A multiple of holes 24 slightly smaller in diameter than the circumscribed circle about an electronic component A are made in the core sheet 23 and the elastic sheet 22.
As shown in FIG. 14a, the electronic component A is pressed part of the way into a corresponding hole 24 in counteraction against the resiliency of the elastic sheet 22, whereupon the electronic component A is held in such a state that one lateral side A1 is exposed on the surface of the jig 20. Then, the jig 20 is fixed to a base 26 by means of screws (not shown) that are inserted through holes 25 in the two shorter sides of the frame 21. When the base 26 is moved under a roller as it is supplied with a conductive paste (ink) on its circumference, the paste is applied onto one lateral side A1 of each electronic component A. Thereafter, the base 26 with the jig 20 mounted thereon is passed through a drying zone so that the applied conductive paste is heated to dry, whereby a side electrode B is formed on one lateral side A1 of the electronic component A.
In the next step, the jig 20 is dismounted from the base 26 and the electronic compound A having side electrode B formed on one lateral side A1 is pushed part of the way to the back surface of the jig 20 until the other lateral side A2 of the electronic component A is exposed on said back surface of the jig 20 (see FIG. 14a). The jig 20 is then remounted on the base 26 and the above-described procedure is repeated to form a side electrode B on the other lateral side A2 of each electronic component A.
This prior art technique has the advantage of achieving improved productivity since side electrodes B can be formed on a multiple of electronic components A in a single step. On the other hand, the following problems are involved in this technique.
(1) The holes 24 in the jig 20 must be preset to have a size that is determined by the cross-sectional shape of each electronic component A and, hence, more than one kind of jig 20 must be provided in accordance with the type of the electronic components A to be processed and this not only increases the production cost of jigs 20 but also requires a substantial burden on the operating personnel in the management of more than one kind of jig. PA0 (2) The jig 20 is produced by a so-called "insert shaping" method, in which core sheets 23 are held between a pair of molds and the cavities formed in the mating surfaces of the two molds are filled with a molten soft material; however, the need to form a number of holes 24 calls for the use of molds having a complex structural design and this also adds to the production cost of jigs 20. PA0 (3) In the absence of any means for supporting the electronic components A that have been pushed part of the way into the corresponding holes 24, the distance by which the lateral sides A1 and A2 of electronic component A project beyond the jig 20 will vary from one component to another and this can potentially cause inconsistency in the thickness of side electrodes B formed on those lateral sides. PA0 (4) If the electronic component A is in a plate form, it cannot be retained in a stable position within a corresponding hole 24 and, hence, the prior art technique cannot successfully be applied to the manufacture of electronic components in a plate form such as thin chip capacitors, network capacitors and network resistors. PA0 (5) The side electrodes B are formed on opposite surfaces of each electronic component A in such a way that they protrude laterally; therefore, when electronic component A that has a side electrode B formed on one lateral side A1 is pushed into a hole 24 toward the back surface of the jig 20, the formed side electrode B will be strongly rubbed against the inner surfaces of the hole 24, whereupon spalling and chipping of the side electrode B may occur to yield defective products.